The application illustrated in this chapter uses CFA procedures to test hypotheses bearing on construct validity. Specifically, hypotheses are tested within the frame­ work of a multitrait-multimethod (MTMM) design by which multiple traits are measured by multiple methods. Following from the seminal work of Campbell and Fiske (1959), construct validity research typically focuses on the extent to which data exhibit evidence of (a) convergent validity, the extent to which different as­ sessment methods concur in their measurement of the same trait (i.e., construct)— ideally, these values should be moderately high; (b) discriminant validity, the extent to which independent assessment methods diverge in their measurement of dif­ ferent traits-ideally, these values should demonstrate minimal convergence; and (c) method effects, an extension of the discriminant validity issue. Method effects represent bias that can derive from use of the same method in the assessment of different traits; correlations among these traits are typically higher than those measured by different methods.